Mohammad ElahiniaAssistant ProfessorIndustrial and
Manufacturing Engineering DepartmentThe University of Toledo419.530.8224Mohammad.elahinia@utoledo.edu

Co-Principal Investigators:

Walter
OlsonProfessor,
Mechanical EngineeringThe University of Toledo

Mark VonderembseProfessor, Information
Operations Technology ManagementCollege of Business AdministrationThe University of Toledo

Project Dates: 08/01/2007 – 12/31/2008

Project Award: FY2007

UT-UTC Designation: UTUTC-AE-1

Abstract:

The University of Toledo University Transportation Center (UT-UTC) has
identified hybrid vehicles as one of the three areas of the research. The activities
proposed in this research proposal
are directed towards the noise, vibration, and harshness (NVH) solutions for hybrid
vehicles. The soaring fuel prices
require imperious steps in developing alternate propulsion technologies. The design
and development of hybrid vehicles
is a critical issue for an economy dependent on an efficient, fast, and secure transportation
system. To date, better
fuel economy has been mainly achieved by combining two propulsion sources (hybridization)
and/or by developing better
managing algorithms for the internal combustion engines. Examples for the hybridization
are the plug-in hybrid electric
and the hydraulic-hybrid vehicles. An example of managing internal combustion engines
is the cylinder on demand as a
solution that Honda has recently introduced. One common problem with these solutions
is excessive noise and vibration
that is caused by switching between the propulsion sources and propulsion modes. To
mitigate this problem there is a
need to develop vibration isolation devices that can provide isolation over a wide
range of frequencies. This proposal
seeks to study the NVH problem of the hybrid vehicles and to introduce isolation mounts
to overcome these issues.

Hydraulic and elastomeric mounts are generally used to dynamically isolating
engines and power trains form the chassis, while statically holding these elements
together. Hydraulic mounts overcome
some of the drawback of the elastomeric mounts. The stiffness and damping of the hydraulic
mounts vary with frequency
and amplitude of vibration. It is possible to design a hydraulic mount that has a
significantly larger static stiffness,
compared to an elastomeric mount, and has a much smaller dynamic stiffness at a specific
frequency. To achieve low
vibration transmissibility, the mount can be tuned to the primary frequency of the
vibration source. On the other hand,
to isolate the high frequency vibration of the engine the mount should have low stiffness
and low damping, which is not
possible to achieve.

This proposal proposes to develop a semi-active mount, which will be realized by improving
the existing hydraulic mounts
through adding a magnetorheological (MR) fluid element. In response to magnetic fields,
MR fluids change their
viscosity, which can be harnessed in a variable stiffness and damping mount. The resulting
mount will provide shock and
vibration isolation over a wide range of frequencies. This extended isolation frequency
range will be achieved through
the variable dynamic stiffness of the MR portion of the mount. This solution will
make it possible to improve the noise
and vibration characteristic of hybrid vehicles with alternative propulsion systems.